Modeling and Rendering go hand in hand. They allow you to see your finished product and make accurate decsions before the project begins. Choice of materials, size of windows and interior colors all come to life through the rendering process.
I can say that other programs can generate more beautiful renderings than Envisioneer, but we aren't looking for fine art here. Another reason I use Envisoneer is it's speed, which in the end saves you money and gets me work. I may add that if you a kind enough to look at my Portfolio page, I think you will find the result more than adequate. Don't get stuck in a 2D world, I quit that back in '97'. 3D is the way to go. You won't regret it.